BTW, does your wife have to carry the bike over her shoulder to get it up to the second floor, or is there enough room for her to walk it up? Because Bafang’s better displays enable a walk mode (P). Simply hold down the - button in assist level 0 and the wheel will rotate at just a couple kph, without having to pedal or engage the throttle. So maybe that feature would allow her both to cover long rides with you as well as commute with assist to her job on the second floor. Honestly though I can’t speak from personal experience how well a front hub drive can climb stairs, having only done that on my dual hub drive e-cumbent while powering both motors simultaneously.